This invention relates generally to the field of collapsible large size shipping containers, and more particularly to an improved form of synthetic resinous clip adapted to perform the joint functions of closing the lid upon a main body of the container, and effecting a seal which prevents removal of the clip until the seal is breached, thereby providing a means for indicating the presence of tampering. Reference is made to my prior U.S. Pat. No. 4,239,149 granted Dec. 16, 1980, the present invention relating to improved structure thereover.
The problem of pilferage of large shipping containers is well known, irrespective of the form of transportation employed. Where the shipping containers are formed of relatively light-weight materials, such as heavy-grade corruagted board, it has been common practice to provide a seal-retaining means in the form of a metal stamping which is engaged upon an inner edge of a main body portion of the container, and which projects through an opening in the lid to be engaged by a frangible seal. To remove the lid from the main body of the container, it is necessary to destroy the seal. In the case of an unauthorized opening, the presence of tampering is immediately revealed.
To facilitate a rapid and convenient securing of the lid upon the container, there have already been developed in the art a plurality of expandable type clips, usually formed of molded synthectic resinous materials which are of an overall expanded size and configuration corresponding to a pair of alignable openings in portions of the lid and the main body of the container. When the container is closed by placing the lid in position, opening in the lid and container are thereby aligned, and the expandable clip is inserted in unexpanded condition to be thereafter expanded to grip the edges of the openings in both parts of the container, and maintain such parts in abutted relation. In one form of clip, there are two separable elements, one of which fits into the other to expand the outer elements to the above described condition. Another type is formed integrally to include a pair of sections foldable about a transversely extending fold line to move the clip between contracted and expanded conditions.
In my above mentioned prior patent there is disclosed a provision for sealing the clip in expanded condition using a flat metallic strip type seal.
While this construction has proved to be satisfactory, the above described seal is relatively expensive, and is of course, not reusable. Since the issuance of the above patent there has become available a molded synthetic resinous seal which cost only a fraction of the cost of the metallic seal. Because of the configuration of the new seal, its use in my earlier construction permits the clip to be partially open without rupture, thereby providing the possibility of undetected tampering.